1. Field of the Invention
The present invention relates to a method of generating road data for use in an on-board (mounted in a vehicle) navigation system.
2. Description of Background Information
Recently, navigation systems to be mounted in a vehicle have been developed and are entering into a stage of practical application, which navigation systems are constructed such that digitized map data is previously stored in a storage medium such as the CD(compact disc)-ROM, map data of a region covering a given area including the present position of the vehicle is read out from the storage medium while the present position of the vehicle is being recognized, so that a map around the location of the vehicle is displayed on a display, and a "vehicle's position" indicating the present position of the vehicle is automatically indicated in the map being displayed.
On the other hand, new roads are regularly constructed for various reasons such as regional development, re-planning of streets, or for relieving traffic congestion. With respect to such new roads, it is possible to display them on the display unit of the system if the user of the navigation system purchases a storage medium on which map data including road data of new roads is recorded. However, with such a procedure, it is necessary for the user to purchase a new storage medium of a high price every time a new road is constructed. This means that the user has to bear the expenses and it is desirable to take a measure to deal with such a problem.